Centrifuge for separating liquids from gases and heavy impurities



March 18, 1947. FLOWERS 2,417,747 7 GENTRIFUGE FOR SEPARATING LIQUIDS mom GASES AND HEAVY mrunnms 3 Sheets-Shet 1 Filed April 23, 1943 m M r M Maid: 18, 1947- A. E. FLOWERS GENTRIFUGE FOR SEPARATING LIQUIDS FROM GASES AND HEAVY IMPURITIES Filed April 23. 1943 3 Sheets-Sheet 2 m m M m M m LW W I w m w 4 M :E i B 2 2 7 S x R w m 6 2 M 3 BBM M I I .l 0 m M. Q m 2 0 6 w m m F .N 0 4 B in.

Much 18, 1947. A. E. FLOWERS 2,417,747

CENTRIFUGE FOR SEPARATING LIQUIDS FROM GASES AND HEAVY IMPURITIES Filed April 23, 1943 s Sheets-Sheet s GAS OIL AND FZaE.

Arrakmerx Patented as. 18, 1947 CENTRIFUGE FOR SEPABATING LIQUIDS FROM GASES AND HEAVY IMPURITIES Alan E. Flowers, Poughkeepsie, N. Y., assignor to The De Laval Separator Company, New York,v N. Y., a corporation of New Jersey Application April 23, 1943, Serial No. 484,197

My invention is a new and improved centrifuge I for purifying liquids.

The object of myinvention is the provision of a centrifugal bowl so constructed that, in one operation, impurities, including gases that are lighter, and other impurities (solid and/or liquid) that are heavier, than said liquid, can be removed therefrom.

I have discovered that one of the difficulties in separation of small particles of solids from liquids containing gases is due to a tendency for small bubbles of gas to attach themselves to such particles and buoy them so that they will not settle. In my improved centrifuge, in making separations of such mixtures there are first removed, as far as possible, all gases from the mixture. The separation of gas is accomplished in a zone as near as possible to the inner face of the liquid to avoid compression and reduction of size of the bubbles, which would reduce their buoyancy and hence their rate of movement through the liquid. The gas-free liquid then moves outward to a zone of much higher centrifugal force. where there are removed from the liquid the particlesof solids and droplets of heavier liquid.

In the accompanying drawings, which show different embodiments of my invention:

Fig. 1 shows a half cross-section of a centrifugal bowl which holds all separated heavy impurities in the bowl shell.

Fig. 2 shows a. similar cross-section of a bowl adapted either to continuously discharge heavy liquids and retain still heavier solids or to continuously discharge both liquids and solids.

Fig. '3 shows the connections between the purlfer bowl, an oil reservoir and the crank case of an internal combustion engine.

Fig. 4 shows an alternative means for discharging gases from the purifier.

Fig. 5 is a partial section on line 5-5 of Fig. 1

' drawn to a reduced scale.

Referring first to Fig. 1: The spindle I of the bowl is adapted to fit into a socket, not shown, by which the bowl is guided and driven. The end 2 of the bowl is permanently fastened to the spindle and secured by a coupling ring 3 to the bowl shell 4 which, with the end 2, encloses a liner consisting of a plurality of frusto-conical plates 5, commonly called discs. Tubes I (preferably from three to six, only one being shown) are inserted through holes in the discs. The discs are held apart by washers 6 surrounding tubes 1 and are centralized and guided by ribs 8 on the spindle I.

' Below the discs 5 and held away from them by a ring 9, farther from the center than the tubes 3 Claims. (Cl. 233-29) I, is a dividing disc'lll which, with its neck ll, forms a partition between an inflow passage l2, l2 for gas containing impure liquid and an outflow passage l3, l3 for degassed and purified liquid. This disc is held'away from the bowl shell and against the ring 9 by ribs I4.

Opening from the tubes I to the spaces between discs 5 are holes IS (in the tube wall and in the washers 6) which distribute impure liquid, inflowing through passage l2, l2 to the spaces between the discs.

v The neck I] of the dividing disc Ill fits closely and revolves around a feed tube IS. A neck I! on the bowl shell 4 fits closely and revolves inside of a guide 18. I

The feed tube It is provided with an annular flange Iii which fits against and is slidable upon a fiat surface 2| of a frame 20 in which the bowl is enclosed. The guide l8 has a fiat upper face which fits against and is slidable upon a flat surface 22 of theframe 20. The feed tube l6 and guide It are thus allowed to centralize with the bowl and to dampedly follow oscillations of the bowl due to unbalance.

The cross holes 23 in the spindle permit escape of gases from the center of the bowl. Holes 24 and 25 in the frame 20 communicate respectively with the liquid feed passage l2 and the purified liquid discharge passage I3.

Several notches 26, preferably semicircular shaped, are cut in the edges of the discs to provide passages through which purified liquid can flow (downward in the figure shown) to the outflow passage l3 without distributing impurities collected in the bowl shell.

The relative diameters of the spindle I and the inlet and outlet passages from the bowl are so chosen that there will be, around the spindle, a liquid free zone into which bubbles of gas separated from the surrounding liquid can escape and through which the-gas can pass to the outlets 23.

Referring to Fig. 3: 231 represents the crankcase of an engine from which a scavenging pump 238 draws used oil and gases and forces them, partly through pipe 224 to a purifier of the type shown in Fig. 1 or Fig. 2, and partly through pipe 224a to-a gas separator 239, of known type,

, from which the oil passes to a storage tank 240,

- Purified and degassed oil flows from the purlfier through pipe 225 to the tank 240, while gases separated in the purifier flow through pipe 223 to the crankcase 231, which is normally under a pressure substantially above that of the surrounding atmosphere, and finally escape through may have an independent outlet 323, in which case it should be provided with an oil trap 3 and pressure control valve 342, as shown in Fig.4.

Referring to Fig. 2; numbers IM to I26 in this figure refer to parts similar tcthose referred to by numbers I to 2G in Fig. 1. .A taper socket I21 in the bowl wall contains an insert I28 with a hole I29 leading to the outside of the bowl. Inside of, and parallel with, the conical portion of the. bowl body shell and held away therefrom by ribs I30, is a second dividing disc I3I forming a partition between the outflow passage H3 for purified liquid and a second outflow passage I32 for heavy liquid impurities. A tight joint between th small diameter end of disc I3I and the bowl shell isprovided by a compressible ring I33. The passage I32 leads to a chamber I34 from which a hole I35 in an adjustable screw I36 leads outside of the bowl.

Though I have shown and described each of my improved bowls asbeing used with the small end down, it can, of course, be used with the small end up if so desired.

While the apparatus may be used for purify ing many different classes of liquids I will,describe, for example, its operation in deaerating and purifying used lubricating oil having mixed with it air, water and solid impurities such as particles of carbon and particles of metal worn off the machine or engine in which it has been used.

Dirty oil fed through hole '24 flows through the passage I2, I2 to the tubes 1 and thence through holes I to the spaces between the discs 5. Here, under the influence of centrifugal force, which progressively increases outward toward the bowls periphery and may average several hundreds, or even thousands, of times the attraction of gravity, any gases contained in the oil are first separated from it, move toward the center and escape through the holes 23. Then the oil, with any solids, water or other impurities heavier than the oil move outward through the interdisc spaces. Because centrifugal force acts stronger on them, anyimpurities heavier than the oil will move radially outward faster than the oil until they contact with the upper sides of the discs, whence they will slide outward along sage I3 through the bowl neck I! is greater than that of the inside of the neck II of the dividing disc II], the pressure on the outflowing purified liquid will be greater than on the inflowing dirty liquid. Hence any leak between the feed tube I6 and the neck I I or between the contacting surfaces of the frame and the flange I9 will be of clean into dirty oil, and not of dirty oil into clean oil; and contamination of the purified liquid will be avoided.

The operation of the bowl shown in Fig. 2 is the same as the bowl shown in Fig. 1 except that, instead of being held in the bowl till it is cleaned, separated heavy liquid impurities can continuously flow out through the passage I32,

- chamber I34 and the hole I in the screw I35,

whichlatter may be adjusted radially outward or inward to control the discharge of that liquid, while separated solids, if they are soft and slimy erggugh, can continuously discharge through hole If it is preferred to hold the solids in the bowl shell, instead of continuously discharging them, an imperforateinsert can be substituted for insert I28 with the hole I29.

While I have found that separations of heavy impurities are more eificient when there are notches in the peripheral edges of the discs. 9. less perfect separation can be made with unnotched discs.

While I have described the operation as if all of the separation of gases from the liquid occurred in the annulus between the liquid free zone and the feed radius and all of the separation of other impurities took place in the annulus surrounding the feed radius, the claims are not to be so interpreted as to exclude any operation in which occurs any separation of a. portion of the gases that may occur in the outer annulus or any separation of other impurities that may occur in the inner annulus.

While I have described my bowl as having a liquid free zone inside of a liquid filled annulus, conditions such as overfeeding, exceptionally high gas content, extreme vibration, etc, may cause some liquid to pass into this zone so that instead of being absolutely liquid free the zone may be only relatively liquid free and contain a mixture of gas and liquid in the form of a froth. The term liquid free, therefore, is not to be so interpretedas to exclude such conditions.

Though I have described my bowl as separating three kinds of impurities, gaseous, solid and liquid, from oil, it can, of course, be used for separating any two or even one kind if the other one or two kinds are not present.

What I claim and desire to protect by Letters Patent is:

l. A centrifuge comprising a central driving spindle, a bowl carried thereby having a frustroconical end, a cylindrical neck extending from I said end and surrounding said spindle, a dividing disc extending parallel with said frustro-conical end and having an extension parallel with said neck and providing, on the outside of the dividing discand extension, an outflow passage for purified liquid and, on its opposite side, an inflow passage for impure liquid, both said passages being concentric with the bowl, a plurality of like discs, spaced apart to form a liner within the bowl between the dividing disc and the other end of the bowl, a plurality of parallel tubes extending through the liner and adapted to receive impure liquid from said inflow passage and distribute it to the interdisc spaces, the inflow and outflow passages being ofsuch large diameter relative to the minimum diameter of the discs that the liquid-free space in the center of the bowl is always of a diameter not substantially less than the minimum diameter of the discs, and a gas outlet leading from said liquid-free space through the central part of the bowl to the outside of the bowl.

2. A centrifuge comprising a central driving spindle, a bowl carried thereby having a frustraconical end, a cylindrical neck extending from said end and surrounding said spindle, a dividing disc extending parallel with said frustro-conical end and inward from near the periphery of the bowl and providing between it andsaid frustroconical end an outflow passage for heavy liquid impurities, a second dividing disc close to and parallel with the first dividing disc and having an extension parallel with said neck and providing between it and the first dividing disc an outflow passage for purified liquid and providing on its opposite side aninflow passage for impure liquid, the outside diameter of the second named dividing disc being less than the outside diameter of the first named dividing disc, a plurality of like discs spaced apart to form a liner within the bowl between the second named dividing disc and the other end of the bowl, a plurality of parallel tubes extending through the liner and adapted to receive impure liquid from-said inflow passage and distribute it to the interdisc spaces, the inflow and outflow passages being of such large diam eter. relative to the minimum diameter of the discs that the liquid-free space in the center 01 the bowl is always of a diameter not substantial- 1y less than the minimum diameter of the discs, and a gas outlet leading from said liquid-free space through the central part of the bowl to the outside of the bowl.

3. A centrifugal bowl comprising a central stem, at frustro-conical bowl end integral with the stem; a bowl shell comprising a. cylindrical portion adjacent the outer edge of said end, a frustro-coniend and acylindrical neck extending therefrom;

and a dividing disc adjacent to and parallel with the frustro-conical and neck portions of the shell and providing, between it and the shell, an outflow passage for purified liquid, and on its opposite side an inflow passage for impure liquid, both said passages being concentric with the bowl, a plurality of like discs, spaced apart'to form a liner occupying the space between the frustro-conical portions of the top and the dividing disc, a plu rality of parallel tubes extending through the liner and adapted to receive impure liquid from said inflow passage and distribute it to the interdisc spaces, there being notches in the peripheries of said discs, the inflow and outflow passages being of such large diameter relative to the minimum diameter of the discs that the liquidfree space in the center of the bowl is always of a diameter not substantially less than the minimum diameter of the discs, and a gas outlet leading from said liquid-free space through the center of the bowl to the outside thereof.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

